1. Ive never pre-heated so I cant answer this one.
2. This will probably help to extend the time between first crack and second crack which is sometimes seen as desirable.
3. The reason most people use the emergency stop is because (in my experience) it can take between 7 and 12 minutes to cool the beans down to 60 degrees inside the drum. Theres an article in the first issue of BeanScene where Ross Quail from Jasper Coffee talks about the importance of fast cooling, which mentions:
He then goes on to talk about some modifications they did to their shop roaster where they decreased cooling time from about three minutes to just over two. He describes the effect of this apparently minor change:"...coffee that has taken a long time to cool presents itself as somewhat flat, lifeless or with a baked falvour. The internal heat (endothermic) must be halted as soon as possible via the cooling process."
So I reckon if a reduction from three to just over two minutes can make that much difference, youre going to lose a lot by letting the beans cool to 60 degrees over about 10 minutes! After using the Gene, this was one of the things that sold me on the Hottop as it cools the beans to stone cold within about 4 minutes.This may all sound like small potatoes, but when we cupped the coffee blind we were bowled over by the quality of the rapidly cooled coffee. Coffee nuances that were, in the past, a little muted were now up front and dancing, and the aromatics of the beans were noticeably enhanced, as well as the sweetness of the coffee itself... to sum up, the extra cooling time meant that the coffee continued to roast while in the cooling tray and was bound to foil all our efforts to produce the style of coffee we were intending to create."
I did talk to the importer, Serge from Go Barista, a while ago about using the emergency stop on a regular basis when we were working out the contents of our Tips and Tricks sheet to supply with the Gene when we sell them. He strongly recommended against doing this as it is designed as an emergency function not a regular operation and doesnt allow the unit to properly cool which could shorten its lifespan. However I guess its up to the individual what they choose to do, and certainly youll probably get better tasting beans if you get them out of the drum as soon as possible; but its good to hear an experts take on this, and ultimately like many things: "ignore the manufactuers recommendations at your own peril!". Serges recommendation was to stop the roast a little early and allow second crack to start near the beginning of the cooling cycle so they dont progress too far and then start to cool.